Problem with fuses

minxystar

Hello All,

Got back from a late shift last night and when I turned on the downstairs light, the fuse blew.

All the other fuses in the house are fine, just this one. Its one of the switch type fuses (I found something similar looking here: http://nextday.diy.com/app/jsp/product/productPage.jsp?productId=92090) and I can't get the switch mechanism to turn back on.

Do I need to buy a new fuse for it? Sorry, if I'm not explaining myself very clearly but my knowledge of electrics isnt that great.

Thanks,

Clare

adaze

If it won't switch back on its probably because there is a fault on the circuit, has anything come loose etc...? You could check all the fittings and switches and ensure that all the screws are tight and that no wires are loose...

ormus

the MCB wont reset, if the circuit is still shorting out. find the fault first or at least isolate it.
ie. simply removing the blown bulb, may do the job.

some info on MCBs.
http://en.wikipedia.org/wiki/Circuit_breaker

baldelectrician

It could be a fault or a faulty MCB.

My betting (if MCB faulty) is an old MEM circuit breaker

What make is it (can you post a picture)?

macman

Do you mean you can't physically reset the trip (in which case it may need replacing), or that when you push it up it immediately trips off (down) again?
If the latter, the fault in the circuit is still present. Turn of all the lights on the downstairs circuit and then see if it will reset. Then turn them on one by one and see which one is causing the trip (you may know that already). The fault is then either in that switch or that light fitting/bulb. Replace bulb first to see if that fixes it.
But I suspect it may be the switch, fitting or the wiring, as normally once the bulb has blown it will let you reset the trip.

mikey72

Check for faults as above, but some MCBs need to be manually switched off first, after they trip. Have you tried switching it off, (all the way down), then trying to switch it back on again?

minxystar

Yes, I have tried switching it off and on again. When I push it up it immediately switches itself off again. I have also switched off the main OFF button on the unit and then tried it but still no luck.

Having had a quick look at the survey / electrics report done when I bought the house it says "the consumer unit accomodates an older consumer unit with updated fusing". The branding of the unit and fuses is Wylex. I don't have a camera to take a photo but having googled, this unit is quite similar, although mine has all of the white type of fuses rather than a mix:



I have worked out which rooms the circuit relates to (fortunately the fuse is marked lights and I know its downstairs only) and have checked the bulbs and switches on 2 of the 4 rooms. I presume the light which triggered the fuse won't necessarily be the one which is the problem (ie if the living room light was the one that caused everything to fuse, is that where the problem lies?

Thank you for your help and patience with this.

Clare

baldelectrician

Remove all lamps and try to reset it. It may be a faulty lamp

Don't keep trying to reset it if there is a fault. Better to get someone in

You should use a competent person for the work, links below
In Scotland:
Individuals registered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/Sear...struction&ID=2
In England and Wales:
http://www.competentperson.co.uk

macman

minxystar wrote: »

Yes, I have tried switching it off and on again. When I push it up it immediately switches itself off again. I have also switched off the main OFF button on the unit and then tried it but still no luck.

Having had a quick look at the survey / electrics report done when I bought the house it says "the consumer unit accomodates an older consumer unit with updated fusing". The branding of the unit and fuses is Wylex. I don't have a camera to take a photo but having googled, this unit is quite similar, although mine has all of the white type of fuses rather than a mix:



I have worked out which rooms the circuit relates to (fortunately the fuse is marked lights and I know its downstairs only) and have checked the bulbs and switches on 2 of the 4 rooms. I presume the light which triggered the fuse won't necessarily be the one which is the problem (ie if the living room light was the one that caused everything to fuse, is that where the problem lies?

Thank you for your help and patience with this.

Clare

Normally you will have one circuit for your upstairs lighting and one for your downstairs lighting. I would start with the switch that originally tripped it. But check the other 2. If you turn off all the lights on that circuit, can you then reset the trip? If not, then you proably have a fault in the switch or circuit, rather than a fault in the fitting or a blown bulb.
Your MCB's appear to be the plug in type, which are easily replaceable, you just obtain one of the same rating as the one that is (possibly) giving trouble.

minxystar

Just spoken to ex bf who was the one who fixed this problem last time. He says that the downstairs lighting MCB is dodgy and thats the problem. Somehow last time he managed to get it working again but even when I have taken it out of the unit completely the switch won't turn on so I think something has gone wrong in the internal mechanism!??!

So, I will replace it with a new one and see what happens. Can I get these in a large B&Q or do I need to go somewhere more specialist? I am in Bristol, BS7.

Thanks,

Clare

macman

You never mentioned a 'last time'...Yes B+Q should do them, but better to go to any decent electrical supplies shop or wholesaler. Take the old one in with you and ensure they match. For a lighting circuit you will probably require a 6 amp one.
PS: make sure you turn off the main switch on the CU before moving or inserting the MCB.